adk deploy agent_engine does not fail when provided with invalid argument to `--agent_engine_config_file `

[rei-arifi]

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Describe the Bug:
A clear and concise description of what the bug is.

Steps to Reproduce:
Please provide a numbered list of steps to reproduce the behavior:

1. Install adk, version 1.26.0
2. Run adk deploy agent_engine --display_name my_agent --agent_engine_config_file ./bogus/path/to/.agent_engine_config.json my_agent

Expected Behavior:
The command should fail and notify the user the file does not exist.

Observed Behavior:
The cli completes the deployment without any error or warning using default config values.

Environment Details:

• ADK Library Version (pip show google-adk): 1.26.0
• Desktop OS:** macOS, Linux
• Python Version (python -V): python3.11

How often has this issue occurred?:

• Always (100%)

This issue is made worse by the fact that the cli changes the current directory silently resulting in relative paths from repository root being wrong when executed from the parent of the agent directory.